Abstract:
The present invention provides an apparatus for efficient and clean handling of concrete admixtures that allows their incorporation into a concrete mixture in a pre-measured and controlled manner. The system provides a novel packaging system to be integrated into the admixture feed devices on a concrete batch mixing truck allowing transfer and incorporation of the admixture material to the concrete without additional handling by the operator. The present invention consists of a tubular package of heavy gauge cardboard or plastic material such as PVC with an easily removable light gauge cover on each end. The cover would be constructed of a material that could be easily displaced when installing the tube into the feeder section of the mixer. The tube is pre-loaded with any variety of clean pre-measured concrete admixtures.

Description:
PRIORITY CLAIM TO EARLIER FILED APPLICATION  
       [0001]    This application claims priority to earlier filed provisional patent application No. 60/264,875, filed Jan. 29, 2001. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    The instant invention relates to a fiber feed tube for use in a concrete batch mixing truck that provides the ability to provide preloaded containers, having measured quantities of reinforcing fibers or other concrete admixtures for use in the admixture feed section of a concrete batch mixer. More specifically, this invention relates to a tube shaped container having sealed ends for the purpose of containing concrete admixtures and serving as a distribution reservoir in a concrete batch mixing system.  
           [0003]    Construction concrete, particularly that used for roads and structures, has long been the mainstay of the American infrastructure. However, the uses to which concrete can be put is limited by the strength of the concrete material. Generally, while concrete has a great deal of strength in compression, it tends to have poor structural properties when subjected to tensile forces. For example, when used as a column where all of the weight is transferred in a linear fashion, the properties of the concrete alone are often sufficient to transfer the weight. However, when used as a beam, strengthening members must be added to assist in transferring the load. It has been a goal in the industry for many years to strengthen the concrete&#39;s structural properties by using certain additives and varying the relative quantity of materials in the concrete mixture. One approach to enhancing the tensile strength of the concrete mixture consists of adding fibers, such as those made of fiberglass, nylon, polypropylene, or other fibrous materials to the concrete mixture. The addition of these fibers increases the tensile strength of the concrete mixture in its cured state. It is therefore common to dose a quantity of concrete with a quantity of these fibers during the mixing stage before the concrete is placed. One of the problems with adding these fibers in raw form at the mixing stage is that they tend to clump together resulting in an uneven distribution throughout the concrete mixture.  
           [0004]    Generally, concrete is made in two ways. The first method is known as the batch method. Simply put, it occurs when an individual creates only one batch of concrete at a time by adding a specified and predetermined amount of ingredients in a mixing caldron or cement mixing truck. Concrete produced using this method is particularly unsuited for the addition of fibers as it is particularly susceptible to the clumping issue identified above. A second method that is more economical is known as the continuous production method. In the continuous production method, concrete is continually produced using a series of conveyor belts and mixing machines and once the mix is completed, it is transported to its final destination. This transportation could be either along further conveyors or through pumps if the material is mixed relatively close to the location at which it will be used or through trucks if the mixing location is remote from the ultimate use location.  
           [0005]    A method used in the prior art for incorporating admixtures into batch mixed concrete includes the use of a “pill”. This method consists of dropping a small paper bag containing a measured amount of admixture material into a known quantity of concrete mixture, as the concrete is mixed, the bag breaks, releasing the admixture into the concrete. Using this method however has drawbacks, as the bag does not always break completely, trapping a portion of the admixture and preventing it from being incorporated into the concrete mixture.  
           [0006]    Another system incorporating the use of an admixture feeder was developed to provide a means for introducing fibrous material or other admixtures into a continuous flow of concrete that is produced using the continuous production method described above. The admixture feeder is comprised of a hopper that holds the admixture material. An aperture is located at the bottom of the hopper through which admixture material is forced. A ram or piston pushes the material through the hopper and out the aperture. As the admixture material emerges from the aperture, rotating fingers agitate it and cause it to fall out of the opening. The material then falls onto a conveyor and is mixed with the other concrete ingredients. The difficulty with this particular system is that the hopper system is a fixed component of the device. Therefore, in order to operate, periodically the ram must be withdrawn from the hopper and the hopper refilled. This is particularly troublesome due to the fact that most concrete admixtures are packaged and sold in large bags or drums that are difficult to handle. In transferring the admixture material from the original packaging into the hopper, there is a risk of contamination and spillage. The operator must scoop or pour the raw material into the hopper that is a fixed component on the mixing machine. Further, there is no real control available to carefully measure the amount of material that is added to the hopper.  
           [0007]    While concrete may be thought of as a rough simple mixture, the science of concrete admixtures actually requires pure materials and carefully measured admixtures. Both the risk of contamination of the admixture and the inability to effectively measure the quantity of admixture material that is added to the hopper can greatly affect the final strength of the cured concrete material. It can therefore be seen that the current state of the art is a less than desirable solution for incorporating admixtures into the concrete mixing process. There is, therefore, a need for the development of an apparatus that will overcome the above noted drawbacks by reducing the amount of handling required in transferring the concrete admixture material to the feeding system. Further, there is a need to provide an apparatus that can provide a controlled and measured dose of admixture for even distribution and incorporation into a concrete mixture. Another object of this invention is to provide an apparatus for packaging concrete admixtures in a manner that allows them to be distributed, sold and incorporated into a concrete system without requiring additional handling by the operator thereby reducing the possibility of contamination or inaccurate measurement.  
         SUMMARY OF THE INVENTION  
         [0008]    In this regard, the present invention provides a solution for efficient and clean handling of concrete admixtures in a pre-measured and controlled manner. The present invention provides a novel packaging system to be integrated into the admixture feed devices on a concrete batch mixing truck allowing transfer and incorporation of the admixture material to the concrete without additional handling by the operator. This system thereby eliminates the possibility of spillage of the admixture material by eliminating the need to scoop or otherwise transfer the material from a bulk package into the feed hopper on the mixing machine. In addition, the admixture material can be carefully pre-measured at the packaging/distribution point in a clean controlled environment rather than in the field where careful measurement is difficult and the risk of contamination is high.  
           [0009]    The present invention consists of a tubular package of heavy gauge cardboard or plastic material such as PVC with an easily removable, yet securely affixed, light gauge cover on each end. The cover would be constructed of a material that could be easily displaced when installing the tube into the feeder section of the mixer and for example could be a heavy coated paper. The tube is pre-loaded with any variety of clean pre-measured concrete admixtures. As can be seen the present invention eliminates the need of handling the admixture materials prior to their incorporation into the concrete and provides a cleaner, more precise distribution system.  
           [0010]    Other objects, features and advantages of the invention shall become apparent as the description thereof proceeds when considered in connection with the accompanying illustrative drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0011]    In the drawings which illustrate the best mode presently contemplated for carrying out the present invention:  
         [0012]    [0012]FIG. 1 is a perspective view of the feed tube package of the present invention;  
         [0013]    [0013]FIG. 2 is a cross-sectional view thereof taken along line  2 - 2 ; and  
         [0014]    [0014]FIG. 3 is an assembly view of the feed tube of the present invention in conjunction with the feed assembly in a concrete mixing device. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0015]    Referring now to the drawings, the feed tube assembly of the instant invention is illustrated and generally indicated at  10  in FIGS.  1 - 3 . As will hereinafter be more fully described, the present invention utilizes a prepackaged, pre-measured container for storing, shipping, handling and introducing concrete admixtures into the concrete mixing process in an effort to reduce overall handling of the admixture during the entire process. The primary advantages provided by the present invention include convenience, increased accuracy and reduced risk of contamination, while further advantages will be discussed and illustrated below.  
         [0016]    First turning to FIG. 1, the feeder tube package  10  of the present invention is shown. The feeder tube  10  is generally cylindrical in shape to facilitate its incorporation into existing concrete mixing technology that is currently in use as will be further described below. While the preferred shape of the feeder tube  10  is shown here as cylindrical, the present disclosure is intended to include any profile shape including a profile shape that is square, triangular or polygonal and will be varied as required to meet the hopper shape of the particular concrete mixing device for which the feeder tube  10  is produced. The wall  12  of the tube  10  can be formed from a variety of materials while the preferred embodiment of the feeder tube  10  is formed from readily available materials such as heavy cardboard or PVC. These materials are selected for the construction of the feeder tube  10  walls  12  based on their availability on the market as well as for their relative durability.  
         [0017]    [0017]FIG. 2 shows a cross-sectional view of the feeder tube  10  pre-charged with concrete admixture material  14 . For the purposes of illustration, the concrete admixture material  14  shown here is fibrous reinforcing material. However, the feeder tube  10  of the present invention may be charged with a variety of different admixture materials including, coloring agents, retarders, accelerators, plasticizers, water reducers, bonding agents, air entrainment agents or any other admixture known in the art. While the remainder of this description will refer to fiber as the admixture material  14  shown in the feeder tube  10 , is should be understood that the fiber is interchangeable with any of the above noted admixture materials and the present invention is intended to include the use of all of them within its scope.  
         [0018]    The feed tube  10  is shown in FIG. 2 containing reinforcing fibers  14 . The fibers  14  are added to the feed tube  10  at a distribution location under clean and controlled circumstances. Bottom cover  16  is first installed onto the feed tube  10  by adhering the bottom cover  16  to the end of the feed tube  10  walls  12  with a conventional adhesive material. Once the bottom cover  16  is secured, the charge of reinforcing fibers  14  is added to the feed tube  10 . Finally, top cover  18  is adhered to the remaining open end of the feed tube  10  also by using a conventional adhesive material in a similar fashion to that described for the bottom cover  16 . The top cover  18  and bottom cover  16  are made from a material of sufficient gauge to hold the reinforcing fibers  14  in the feeder tube  10  and to resist puncture or damage during the normal handling of the feeder tube 10 . However, the covers  16 ,  18  should be light enough in gauge to allow their intentional displacement when the feeder tube  10  is placed into a feed hopper of a concrete mixing assembly. For example, top cover  18  and bottom cover  16  may be made from a heavy gauge coated paper or a lightweight plastic cellophane material. The purpose of the covers  16 ,  18  is to retain the contents of the feeder tube  10  during storage, handling and distribution of the feeder tube  10  from its point of manufacture to its ultimate point of use while also protecting the contents from moisture or other contamination.  
         [0019]    As was discussed above, the science involved in formulating concrete mixtures is relatively precise and requires that the materials added to the mixture be carefully measured and free from contamination before their incorporation into the concrete mixture. This level of control is required in order to insure that the final cured concrete product will achieve the required strength and have a uniform appearance. By using the feeder tube  10  of the present invention a high degree of control over the admixture material can be obtained. The reinforcing fiber  14  can be added to the interior of the feeder tube  10  in a precisely measured quantity and the top cover  18  can be sealed insuring that the quantity of fiber reinforcing  14  in the feeder tube  10  remains the same. In this manner, a single dose of reinforcing fiber  14  can be measured and provided to the cement mixing machine operator in the field without requiring him/her to handle or measure the reinforcing fiber  14  directly. Further, since the quantity of reinforcing fiber  14  within the feeder tube  10  is known, the amount of concrete material that can be produced corresponding to the quantity of reinforcing fiber  14  is also known and therefore quality control is easier to monitor.  
         [0020]    Since the feeder tube  10  is sealed at its original point of distribution, the reinforcing fiber  14  contained therein is also of a known purity level. The risk of contamination due to the handling of the finer reinforcing  14  in the field is greatly reduced. This particularly advantageous due to the conditions typically encountered in the field. Generally, a construction site where batch mixing of concrete occurs is muddy and littered with construction debris and the measuring equipment that an operator would have on a concrete mixing machine would generally consist of a rusty, dented coffee can. When loading the admixture feed hopper in the prior art, the operator would simply scoop an approximate amount of the reinforcing fiber  14  material into the hopper using his dirty, beat-up measuring tools. It can be seen that by handling the materials in this fashion it would be very difficult to measure precise amounts of reinforcing fiber  14  or to insure that it is transferred into the hopper without contamination.  
         [0021]    [0021]FIG. 3 shows a sectional view of the general relationship of the component parts of the preferred embodiment of the fiber feed tube  10  as it is incorporated into the fiber feed section  20  of a concrete mixing device. The fiber feed section  20  is comprised of a receiving tube  22 , an extruding means  24 , an agitating means  26 , and a conveyor means  28 . The receiving tube  22  is generally cylindrical and capable of receiving the fiber feed tube  10  of the present invention and is only of a slightly larger diameter than the outer wall  12  of the fiber feed tube  10  so as to securely support the fiber feed tube  10  in the fiber feed section  20 . The fiber feed tube  10  is placed into the receiving tube  22  having both top cover  18  and bottom cover  18 ,  16  in place. The receiving tube  22  has an aperture  30  at the bottom end opposite the one into which the fiber feed tube  10  is received. The bottom aperture  30  is mounted above the agitating means  26 .  
         [0022]    Extruding means  24  includes a plunger  32  at the lower end. The plunger  32  is circular in shape and only slightly smaller than the diameter of the walls  12  of the feeder tube  10 . The relationship between the diameter of the plunger  32  the receiving tube  22  and fiber feed tube  10  is an important aspect of the present invention. The fiber feed tube  10  has a wall thickness T shown in FIG. 2. The diameter of the receiving tube  22  is only slightly larger than the diameter of the fiber feed tube  10  so that the fiber feed tube is securely retained. The plunger  32  is only slightly smaller than the diameter of the feed tube less thickness T to allow plunger  32  to be extended freely up and down within the fiber feed tube  10  to smoothly and freely extrude the reinforcing fiber material  14 . The wall thickness T of the fiber feed tube  10  can be varied to accommodate the required receiver tube  22  and plunger  32  diameters as required between the varying manufacturers of concrete mixing devices. Once the feeder tube  10  is placed into the receiving tube  22 , the extruding means  24  lowers the plunger  32  into the feeder tube  10 . When the plunger  32  encounters the top cover  18  of the feeder tube  10 , it displaces the material of the top cover  18  by tearing through it, thereby allowing the plunger  32  to continue downward into contact with the reinforcing fiber  14 . As the plunger  32  continues to move downward, the reinforcing material  14  is further compressed and exerts sufficient pressure on bottom cover  16  to cause it to rupture, allowing the reinforcing fiber  14  to be released into the bottom aperture  30  of the feeder section  20 . As the plunger  32  continues to move downward toward the agitating means  16 , the plunger  32  forces any material inside the feeder tube  10  out of the bottom aperture  26 . The extruding means  24  can be retracted so that the plunger  32  clears the top of the feeder tube  10  allowing the empty feeder tube  10  to be removed from the receiving tube  22  and a new fully charged feeder tube  10  to be installed by the operator.  
         [0023]    A flexible rubber shoe  34  containing an aperture  36  is set at the bottom aperture  30 . The bottom aperture  30  and the aperture  36  of the rubber shoe  34  are aligned. A gate  38  is slideably mounted between the rubber shoe  34  and the fiber feed tube  10 . The gate  38  to can be slid between the bottom aperture  30  and the aperture  36  of the rubber shoe  34  obstructing the flow of material from the feed tube  10 . The rubber shoe  34  is fastened above agitating means  26  over opening  40  in agitating means  26  where bottom aperture  30 , aperture  36  and opening  40  are aligned to allow material flow, provided the gate  38  is in an open position. As the reinforcing fiber  14  flows from the fiber feed tube  12  through opening  40  and into the agitating means  26 , the reinforcing fiber  14  is raked so that is separated and generally evenly distributed for incorporation into concrete mixture  42 . As the fibrous material  14  is raked, it falls in a uniform fashion onto a conveyor means  28 . The conveyor means  28  includes a moving belt  44  that holds concrete mixture  42  whereby as the fiber reinforcing  14  falls in a uniform pattern across the concrete mixture  42  on the moving belt  44  it is uniformly incorporated into the concrete mixture  42 .  
         [0024]    It can be seen that the fiber feeder tube  10  accomplishes all the objectives of the present invention. The fiber  14  is distributed evenly within the concrete mixture  42 , thereby strengthening the hardened concrete product. Further, the fiber material  14  is packaged, transported and handled to its final incorporation into the concrete mixture  42  without additional handling required on the part of the operator of the concrete mixing assembly  20 . Finally, a great deal of control over the quantity of fiber reinforcing  14  employed and purity of the material is exercised. The device and method of the present invention therefore permit the continuous addition of a variety of concrete admixtures onto the concrete mixture in a very efficient manner.  
         [0025]    While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and rearrangements of the parts may be made without departing from the spirit and scope of the underlying inventive concept and that the same is not limited to the particular forms herein shown and described except insofar as indicated by the scope of the appended claims.