Patent Publication Number: US-2007104020-A1

Title: Concrete delivery truck

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
      This is a divisional of U.S. patent application Ser. No. 10/368,107 filed Feb. 15, 2003. 
    
    
     FIELD OF THE INVENTION  
      This invention relates to concrete ingredient delivery trucks; and, more particularly, it is of an improved concrete ingredient delivery truck of that type which includes a mixing means and, also, includes a fiber strand chopping device for mixing of the ingredients and short chopped fiber strand lengths at a job site and selectively depositing the mixture to set up as fiber reinforced concrete.  
     SUMMARY OF THE INVENTION  
      This invention Is of an apparatus and process for chopping and depositing short reinforcing fiber strand lengths into flows of separate concrete ingredients and water from a concrete ingredient delivery and mixing truck for job site mixing of short strand lengths, the concrete ingredients and the water and depositing the mix at the job site to set up there as fiber reinforced concrete.  
      The invention relates both to a process and to an apparatus on a concrete ingredients delivery and mixing trick for: 
          A) chopping, at a job site, short fiber reinforcing strand lengths from a continuous fiber strand supply on a spool carried on the truck by a strand drawing, chopping and ejecting means on the truck;     B) depositing the chopped fiber strand lengths on an output flow of concrete ingredients and water from the truck, said output flow comprising: 
            a) a flow of sand, usually wet,     b) a flow of rocks, usually wetted, and,     c) a flow of Portland cement;    
            C) mixing the chopped fiber strand lengths and concrete ingredients to form a reinforced concrete mix by a mixing means on the truck in an output flow directing trough with a movable discharge end; and,     D) dispensing the mix at the job site to set up as fiber reinforced concrete.        

     BACKGROUND  
      It is well known that there are concrete trucks for depositing concrete at a job site, for example, into a foundation ditch. Generally, there are two types of such trucks: 
          a) a first type of truck, which includes a rotatable, generally cone shaped, downwardly tilted turning drum in which a charge of cement, sand, rocks and water, and, sometimes, short lengths of reinforcing fiber lengths, are mixed in the turning drum while in transit to a job site and to be dispensed at the job site from the drum as a flowable mix onto one end of a chute extending from the truck; and     b) a second type of truck, to which this invention is relevant, which is used to transport and dispense separate concrete ingredients in separate compartments which are carried to the Job site by the truck; however, the ingredients are mixed at the job site, rather than in transit to the job site, and, then, they are dispensed from the truck.        

      With the second type of truck there has been a problem of adding short fiber reinforcing lengths to the combined output from the truck flow of separate concrete ingredient flows, so that, in the combined out flow from the truck, the short fibers lengths are not clumped or grouped, but, rather, are randomly dispersed generally in a quite uniform reinforced concrete mix. Past efforts to introduce chopped short fiber lengths into a flow of concrete ingredients have resulted in clumping or grouping of the fibers; and, as a consequence, the tensile strength enhancement sought of the concrete mix, when set, is not achieved. Past efforts have included hand dispensing of packaged pre-chopped short fiber lengths by dropping short lengths of chopped fiber directly onto an out flow of the concrete ingredients from the truck.  
      Although not described as being for a chopper for use on a truck, U. S. Pat. No. 5,316,197 describes an apparatus for depositing short fiber lengths onto a conveyor system; and this patent sets forth in some detail the past prior art problem, namely that of clumping and grouping which this invention specifically addresses. In short, this invention is of an apparatus and of a process for developing a uniform concrete mix of concrete ingredients, water and short cut lengths of fiber strand at a job site and selectively depositing the mix on a delivery truck of the second type described above.  
      A general object of this invention is, therefore, to provide an apparatus and process which overcomes the past fiber strand grouping and clumping problem involved in delivering separate fiber strand reinforced concrete ingredients to a job site, mixing the ingredients at the site and depositing them to set up as fiber reinforced concrete in a structure being erected.  
     SUMMARY OF THE APPARATUS INVENTION  
      This invention is of an apparatus which includes a housing mounted on a truck constructed to transport and store a continuous fiber filament strand on a spool in the housing, and a strand withdrawing, chopping and ejecting means powered by a pneumatic motor in a cutting chamber in the housing with a discharge port for passage of the cut short fiber strand lengths under the influence of the exhaust from the motor. The process includes insinuating the cut strand lengths, preferably, at the confluence of separate conveyor conducted flows of sand, rocks, water and portland cement, as that mix is introduced from above into the mouth of a bowl with a lower discharge opening into one end of mixing trough, which usually includes an auger type mixer. The apparatus also includes conventional air flow metering means to control the revolutions per minute of the motor and, hence, the amount per cubic yard of cut fiber lengths introduced into the reinforced concrete mix.  
      Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although many methods and materials similar or equivalent to those described can be used in the practice of the present invention, the preferred methods and materials are described.  
      A strand, as that term is used herein, is a long or continuous length of a generally parallel, somewhat twisted, plurality of fiber reinforcing filaments which have been wound onto a supply spool. A short chopped fiber strand length is a length within the length range conventionally chopped from a continuous strand length in the conventional spray up method of making fiber reinforced materials; and its precise length of the short fiber strands is dictated by the circumference of the chopper elements and the circumferential spacing of the cutter blades from one another. 
    
    
     DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic drawing of the process.  
       FIG. 2  is a general view of a portion of the invention on a portion rear of a conventional concrete truck ingredient delivery and mixing truck of the type described above with the inventive apparatus being generally illustrated.  
       FIG. 3  is an exploded view of the parts of the fiber strand drawing, chopping and ejecting apparatus. 
    
    
     DESCRIPTION OF THE INVENTION IN A PREFERRED EMBODIMENT  
      Referring to the schematic drawing,  FIG. 1 , the rear of a truck  10  is indicated. The truck includes, as is conventional, in addition to a means, not shown, to introduce water into concrete ingredients, a first, second and third main chamber,  12 ,  14  and  16 , each including a conveyor means, or concrete ingredient moving means,  18 ,  20  and  22  of a conveyor system including a drive means, and a funnel type structure, as indicated at  24 , with an open mouth  26  at a common output confluence zone  25  for receiving the discharge flows of the respective conveyor means to direct them onto the collection end of a swingable trough defining chute  28  which includes a concrete ingredient moving and mixing means  30 , usually an auger type to travel the mix to the discharge end  17  of the chute. The drawing, chopping and ejecting means of this invention is designated by the numeral  32 . It has a housing  34  and a chopped fiber length discharge opening  36 , preferably located closely adjacent and just above the aforesaid confluence zone  25  with the output from the chopper rollers being directed through the discharge opening and toward the ingredients to be mixed and discharged from the chute.  
      A more detailed description of the conventional structure of the type of concrete ingredient delivery and mixing truck on which the chopping apparatus is installed will not be provided so that this specification does not become prolix.  
      In general, the apparatus of the invention includes the housing  34  with an access door  35 , or access means. Within the housing, there is a chopping chamber  38  with a fiber strand chopper means  40  in a fixed position on the housing floor  42  below a horizontal wall  41  separating the housing interior into the chopper chamber  38  and an adjacent supply chamber  44 . The chopper means  40  serves the functions of drawing fiber strand from a spool  45 , chopping short lengths from it and ejecting the short fiber strand lengths. The chopping chamber  38  includes an outlet port which may include a mouth defining portion  26  to direct the output of chopped strands from the chopping chamber onto the concrete ingredients to be mixed together. In the chamber separating wall  41  there is a smoothly rimmed opening  43  for passage of the strand as it is drawn by the chopper means from a spool  45  on a shaft  47  in the supply chamber  44  on which it may rotate. Means mounting and positioning the housing  50  on the rear truck panel, preferably on the rear panel, are provided, such as a set of screws the head of one of which is designated by the numeral  51 . The access door  35  includes the mutually cooperating locking means  53   53 ,′ as shown; or any other suitable means to hold the door closed or to open it may be employed.  
      As seen in  FIG. 3 , the chopper means  40  is generally a conventional type. It includes a blade equipped cutter roller  61  and an opposing driving roller  63  which, as shown, are on a fixed frame  65  and driven in a conventional manner by a pneumatic motor  67  also mounted on the frame  65 . The motor has a gas inlet  69  and an outlet  71 , the latter being provided with a tubular exhaust flow directing means  73  which feeds the exhaust into a closed, somewhat pressurized, collection and ejection space  98  between the frame and a cover  76  in which there is a cut strand discharge opening  26 . This opening or mouth  76  may be provided with a tubular hose  26 ′ for directing the severed short fiber lengths away from the cutter means. The fixed frame  65  includes an extending portion or lug  81  in which there is hole or mouth  91  for introducing strand into the cutting space  98 .  
      In use, the end of the strand is fed through the rimmed hole  43  in the wall  41  and into the cutter chamber  44 , through a smooth hole  91  in lug  81  and by a pinch or idle roller  78  of the cutter means  40 . The cover  76 , which together with the frame surface  79  closes a space  98  where the actual chopping takes place, is replaced and secured by the bolt  70 . The lug  81 , on the frame and the cutout  83  in the cover are helpful in positioning, orienting and maintaining the parts in the correct relation to one another in assembly. The motor, when energized by a supply of compressed air, drives the cutter means; and its exhaust, is released into the space  98  between the frame and cover, which causes a force that tends to separate the cut fiber strand lengths and move them out of the housing through the mouth structure  26 , which may include a hose length  26 ′ and onto the concrete ingredients to be mixed in the mixing means  30  of the truck at a job site.  
      While the principles of the invention have been made clear in the illustrative embodiment, there will be immediately obvious to those skilled in the art that many modifications of structure, insofar as arrangement, proportions, and the elements, materials, and components and as well in the process used in the practice of the invention, can be made, which are particularly adapted to specific environments and operative requirements described hereon, without departing from those invention principles. The appended claims are therefore intended to cover and embrace any and all such modifications, within the limits of the true purview, spirit and scope of the invention as set forth in the claims and within the doctrine of equivalents.