Mobile concrete mixer

{
  "publication_number": "US4832498A",
  "country": "US",
  "kind": "A",
  "title": "Mobile concrete mixer",
  "abstract": "A mobile concrete mixer comprising an elongated wheeled frame adapted to be connected at its forward end to a prime mover such as a truck or the like to enable the mixer to be moved from one location to another. An elongated conveyor support is pivotally mounted on the wheeled frame and has a hydraulic cylinder operatively secured thereto to enable the rearward end thereof to be raised to the desired dicharge height. A conveyor belt is movably mounted on a conveyor suport and has an elongated concrete mixer hopper positioned thereover. The lower end of the concrete mixer hopper is open to provide communication between the interior of the hopper and the upper portion of the conveyor belt. A plurality of vertically disposed shafts are rotatably positioned within the mixing hopper and have helical conveyor-like portions mounted on the lower ends thereof and laterally extending mixing paddles positioned thereabove. The rotation of the mixing devices elevates and mixes the aggregate materials in the hopper.",
  "claims": [
    "1. A mobile concrete mixer, comprising, an elongated wheeled frame means having a first end and a second end, means on the first or second end of said wheeled frame means for connection to a prime mover, an elongated conveyor support means, having forward and rearward ends, pivotally mounted at its forward end to said wheeled frame means and being pivotally movable between a lowered transport position and a selectable elevated operating position, means for raising and lowering said conveyor support means, a conveyor belt means movably supported on said conveyor support means and including an upper conveying portion and a lower return portion, means for moving said conveyor belt means whereby said upper conveying portion moves from the first end of said conveyor support means to the second end thereof, an elongated concrete mixing hopper means mounted above at least a portion of said upper conveying portion, said hopper means having upstanding forward and rearward ends, opposite sides, an upper end, and an open lower end which is positioned above said upper conveying portion, said rearward end of said hopper means having a discharge opening formed therein at least at its lower end, said hopper means adapted to receive concrete materials therein through its upper end, a mixing means in said hopper means for mixing the concrete materials therein, and means for selectively controlling the movement of said conveyor belt means whereby said conveyor belt means may be either operated to convey the concrete materials from said hopper means through said discharge opening after the concrete materials have been mixed or to convey the concrete materials longitudinally within said hopper means as the mixing operation is taking place, said mixing means comprising a plurality of substantially vertically disposed rotatable shafts positioned in said hopper means and having upper and lower ends, the lower ends of said shafts being positioned adjacent said upper conveying portion, the upper ends of said shafts being positioned adjacent the upper end of said hopper means, said shafts having helical conveyor flighting mounted thereon at least on the lower ends thereof for moving the concrete materials upwardly and outwardly from the lower end of said hopper means as said shafts are rotated, and means for selectively rotating said shafts.",
    "2. The mobile concrete mixer of claim 1 wherein said conveyor flighting is positioned only at the lower ends of said shaft.",
    "3. The mobile concrete mixer of claim 2 wherein at least one mixing paddle means is mounted on each of said shafts above said conveyor flighting.",
    "4. The mobile concrete mixer of claim 3 wherein said mixing paddle means comprises an arm means secured to said shaft which extends laterally therefrom, and a mixing plate means at the outer end of said arm means.",
    "5. The mobile concrete mixer of claim 3 wherein a plurality of mixing paddle means are mounted on each of said shafts.",
    "6. The mobile concrete mixer of claim 1 wherein said means for rotating said shafts comprises a motor means operatively connected to the upper ends of said shafts.",
    "7. The mobile concrete mixer of claim 6 wherein said motor means is mounted on the upper end of each of said shafts.",
    "8. The mobile concrete mixer of claim 7 wherein a cover means extends over the upper end of said hopper means, said shafts extending upwardly through said cover means, said hydraulic motor means being mounted on the upper ends of said shafts above said cover means, said cover means being movable between open and closed positions.",
    "9. The mobile concrete mixer of claim 8 wherein said cover means is hingedly secured to said hopper means and wherein said hydraulic motor means and said shafts are mounted on said cover means for movement therewith whereby said shafts will move out of said hopper means when said cover means is opened.",
    "10. The mobile concrete mixer of claim 1 wherein said conveyor flighting has upper and lower ends and wherein the lower end of said conveyor flighting is closely positioned above said upper conveying portion.",
    "11. The mobile concrete mixer of claim 1 wherein a plurality of said shafts are positioned in said hopper means and are arranged in at least first and second longitudinally, extending rows, said first row of said shafts being positioned adjacent one of said sides of said hopper means, said second row of said shafts being positioned adjacent the other side of said hopper means.",
    "12. The mobile concrete mixer of claim 11 wherein the shafts in said first row are longitudinally staggered with respect to the shafts in said second row."
  ],
  "description_excerpt": "This invention relates to a concrete mixer and more particularly to a mobile concrete mixer which may be utilized to mix concrete materials in either a continuous or batch type manner. Further, the mobile concrete mixer of this invention includes means for selectively vertically adjusting the discharge height of the same.\n\nHistorically, concrete has been mixed in a variety of devices such as rotary drum mixers, pug mills, vertical shaft turbine mixers, tub type ribbon mixers, etc.\n\nRotary drum mixers are, by nature, limited in mixing speed due to the presence of centrifugal force within the drum which requires longer mixing time to achieve the required mixing. Rotary drum mixers are normally tilted to discharge the materials therefrom which means that the mixed concrete must be gathered in a collecting hopper to regulate transfer into hauling units. The requirement of such hoppers, and the bulk of the drum design, results in discharge height requirements which are not compatible with mobile concrete plants.\n\nTurbine mixers, which normally have a vertical shaft and mixing plows rotating within a circular housing, will mix the concrete materials faster than a rotary drum mixer but the diameter of the turbine mixers necessarily becomes excessively large when the capacity of the same is increased to equal the desired batch capacity of approximately ten cubic yards.\n\nTub type ribbon mixers are likewise large and bulky and require a discharge collecting hopper or a discharge conveyor which is not suitable for use with mobile concrete plants.",
  "cpc": [
    "B01F 27/0726",
    "B01F 27/2322",
    "B01F 33/502",
    "B28C 5/365",
    "B28C 9/04"
  ],
  "ipc": [
    "B01F 15/00",
    "B01F 7/00",
    "B28C 5/36",
    "B28C 9/04"
  ],
  "inventors": [
    "Robert C. Milek"
  ],
  "filing_date": "1988-06-06",
  "publication_date": "1989-05-23",
  "grant_date": "1989-05-23",
  "priority_date": "1987-12-11",
  "application_number": "US-20268188-A",
  "family_id": "26829546",
  "cited_by_count": 18,
  "citations": [
    "US3263971A",
    "US3759492A",
    "US3904723A",
    "US3917236A",
    "US3942772A",
    "US4104737A",
    "US4610545A"
  ]
}