|Publication number||US3612491 A|
|Publication date||Oct 12, 1971|
|Filing date||May 21, 1970|
|Priority date||May 21, 1970|
|Also published as||CA951718A, CA951718A1, DE2123129A1|
|Publication number||US 3612491 A, US 3612491A, US-A-3612491, US3612491 A, US3612491A|
|Inventors||Mckillop Robert W, Stanis William|
|Original Assignee||Rex Chainbelt Inc|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (4), Referenced by (8), Classifications (8), Legal Events (1)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent Inventors Robert W. McKillop Milwaukee; William Stanis, Muskego, both 01 Wis. Appl. No. 39,495 Filed May 21, 1970 Patented Oct. 12, 1971 Assignee Rex Chainbelt Inc.
CONCRETE HOLDING MIXER 6 Claims, 1 Drawing Fig.
US. Cl 259/161, 259/177 Int. Cl B28c 7/00 Field of Search 259/ 161 162,164,165,160,169,l70,172,l75, 176,177, 153, l4,30;214/630  References Cited UNITED STATES PATENTS 2,357,583 9/1944 Franco 214/630 3,038,705 6/1962 McDermott.. 259/175 3,185,450 5/1965 Duecy 259/172 3,526,392 9/1970 Buelow 259/161 X Primary ExaminerRobert W. Jenkins AttorneysErnst W. Schultz and Joseph J. Jochman, Jr.
ABSTRACT: A concrete mixer is adapted for use as a temporary concrete holding drum by providing a conveyor for charging the mixer drum with premixed concrete for holding or discharge directly to the mixer discharge chute. The entire unit is transportable and the conveyor is separately demountable therefrom such that the mixer may be operated as a C011- ventional transit mixer.
PATENTED um I 2 I97! @yoberyggiz/ a lyornqrq CONCRETE HOLDING MIXER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention pertains to the art of concrete delivery and placement, and more particularly to a concreteholding means for use intermediate the delivery of readymixed concrete to a construction site and its final placement. The concrete-holding means includes a concrete mixer fed by a belt conveyor and adapted to receive the supply of concrete delivered to the site, such as by truck mixers, and to accommodate surges in such supply, and to simultaneously provide a discharge of concrete for final placement either continuously or intermittently, as required.
2. Description of the Prior Art.
The supply of concrete to the location of the construction of a building or other structure is often provided by transit-type concrete mixers or, as they are more commonly known, truck mixers. The advantages of supplying ready-mixed concrete are well known and include elimination of on-site concrete batching and storage of raw materials.
It is often difficult, however, to coordinate the actual placement of concrete in the structure with the supply of readymixed concrete being delivered by a fleet of truck mixers. Thus, a slowdown or unexpected halt in the placement or pouring of concrete may cause a backup of truck mixers waiting to discharge concrete. Such a delay is very costly to the concrete supplier who is largely dependent on the number of trips each truck mixer makes. In addition, a backup of trucks can interfere with operations at the construction site and, particularly in metropolitan areas, can impede the flow of local traffic and create traffic hazards.
The rate at which concrete is being poured may, at times, exceed the delivery rate. This problem often occurs or is compounded when the truck mixers are required to be maneuvered into restricted or other difficult-to-reach positions be fore discharging the concrete. The result is, of course, delays in the final placement of concrete.
Various devices adapted to facilitate the handling and placement of concrete are shown in the prior art. It is, thus, known to provide a temporary storage or holding bunker which receives ready-mixed concrete from truck mixers and form which portions may be selectively withdrawn and elevated for placement. This apparatus is shown in U.S. Pat. No. 2,357,583 and was developed for use with construction methods and equipment in which elevators operating in towers erected at the job site are used to lift concrete for placement.
The above identified patent had as a primary object the solution of the problem caused by the difficulty in coordinating the delivery and final placement of ready-mixed concrete, as previously discussed. The system and apparatus disclosed therein were of limited general utility and of complex construction, and have been replaced by simpler and more rapid means of elevating concrete for placement. The problem of coordination between delivery and placement, however, has remained and no satisfactory solution has been found for use with modern methods and apparatus; and the problem is, of course, not limited to situations where delivered concrete must be elevated for placement, but exists in any construction job where the ready-mixed concrete must be poured in a place inaccessible to the truck mixer and/or where the demand may be erratic or a continuous supply critically necessary.
It is common today, in building large concrete structures of various kinds, to move concrete from the point of delivery directly to placement by means of a bucket suspended from the boom of a crane. This method has gained wide acceptance because of its versatility and the utilization of equipment commonly employed in various other operations on the construction site. Truck mixers discharge concrete directly into the bucket which generally can be filled a half dozen or more times from an average capacity mixer. The truck mixer must, therefore, await the return of the bucket each time with the consequent loss of considerable truck time. On the other hand, if the truck mixers must back or otherwise move one at a time into a restricted position to unload, as is often the case, considerable pouring time may also be lost while the empty truck is leaving and the next one is moving into position to unload.
Another commonly used means of moving concrete from the place of delivery to remote placement in a structure is a concrete pump. A concrete pump is generally fed by a relatively small hopper mounted on the unit and, as is known in the art, an uninterrupted even flow of concrete supplied to the hopper is very critical.
Belt conveyors are also often used to carry concrete to placement in remote areas of a job site. In this placement method, it is equally important to be able to maintain a continuous supply of concrete to the belt conveyor and to be able to halt the supply if final placement is stopped for any reason.
It is, therefore, apparent that the ideal delivery-placement system would include an intermediate concrete holding means wherein the supply thereto could be made completely independently of the discharge therefrom. It is also important, as is known and disclosed in the prior art, that concrete held in place for more than short periods be mixed or agitated to maintain uniformity in the mix and avoid segregation of the ingredients.
U.S. Pat. No. 3,185,450 shows a mobile apparatus adapted to receive and distribute a concrete mixiThe apparatus includes a mixing skip feeding a belt conveyor which, in turn, discharges into a chute for final placement. Though designed primarily for mobile placement of concrete, this type of device could also be used as a stationary intermediary for the receipt of concrete from a truck mixer and the selective redistribution for placement either directly or by a bucket or other means. A
- particularly critical disadvantage, however, exists in the inability of this device, as disclosed, to simultaneously receive and discharge concrete, as required in order to avoid the costly delays described above.
A portion of the concrete batch plant shown in U.S. Pat. No. 3,446,487 includes a horizontal mixer fed by a belt conveyor. This combination provides a disclosed ability for selective or simultaneous charging and discharging with temporary holding and mixing in the horizontal drum. This mixer, however, is designed particularly for use in a batch plant, and the elaborate concrete transfer mechanism is specifically adapted for operation as part of the batching system. The horizontal mixer is, thus, not readily adaptable to operation outside the system for which it was designed. Additionally, its cost may exceed by as much as four times the cost of a mixer of the type used on a truck mixer, and its modification for limited use outside a batch plant would be economically impractical.
SUMMARY OF THE INVENTION In the present invention, a conventional inclined axis concrete mixer provides a temporary holding and mixing station to minimize the adverse effects of unavoidable lack of coordination between the supply of ready-mixed concrete to the construction site and its final placement in the structure. Concrete is supplied to the charging hopper of the mixer by a belt conveyor extending from a substantially low level at the head end of the mixer over and in closely-spaced relation to the top of the drum, and terminating over the hopper.
One truck mixer can discharge its full load of concrete onto the conveyor without delay and move out of the way for the following truck mixer. The concrete is carried to the charging hopper of the stationary mixer, from which it is funneled into the mixer drum. The concrete may be temporarily held and mixed in the drum or simultaneously discharged by opposite rotation of the drum in a known manner.
The conventional transportable mounting of the mixer and conveyor provides necessary portability and the conveyor is demountable therefrom such that the remaining unit can be towed by a standard tractor and operated as a transit mixer.
BRIEF DESCRIPTION OF THE DRAWING The drawing shows a side elevational view of the concrete holding mixer in its preferred embodiment mounted on a semitrailer.
DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, a portable concrete holding mixer includes a conventional inclined axis concrete mixer 11 mounted on a semitrailer l2 and to which concrete is supplied by a belt conveyor 13 mounted atop the mixer 11.
The mixer drum 14 is a frustoconical inclined axis type supported at its forward and rearward ends for rotation about its axis. The forward or head end is supported by a pedestal 15 and the rearward end by a rear upright frame member 16. The pedestal l5 and upright frame member 16 are fixed, respectively, to the forward and rearward ends of a pair of longitudinal frame members 17 which are, in turn, secured to the trailer chassis 18.
The drum 14 is driven by an annular drum sprocket l9 fixed to the outer periphery of the drum. A drive chain 20 interconnects the drum sprocket 19 and a drive sprocket 21. The drive sprocket is powered through a speed reducer 22 and either a mechanical or hydraulic transmission 23 by an engine 24 mounted on the trailer chassis 18 forwardly of the pedestal 15.
Concrete (or a batch of concrete ingredients) is supplied to the mixer drum 14 through a charging hopper 25 disposed adjacent the open rearward end of the drum. The hopper is constructed and positioned to funnel the concrete down and into the interior of the drum. As is well known in the art, the interior drum wall is provided with a spiral mixing and discharge blade 26. When the drum is rotated in one direction, the blade carries the concrete to the closed head end of the drum, and rotation of the drum in the opposite direction moves the concrete upwardly and rearwardly where it is discharged over the lip 27 defining the open end of the drum.
A discharge chute 28 is attached by means of a vertical axis pivot 40 to the upright frame member 16 such that its upper receiving end is always positioned directly below the discharge hopper 39 and the lip 27 of the drum for the receipt of concrete discharged therefrom. The chute 28 directs the concrete by gravity either to final placement or to a receiving means such as a bucket B by which the concrete may be moved to a location not accessible for direct placement from a mixer.
The belt conveyor 13 is of common construction and includes a pair of siderails 29 between and at the ends of which are mounted the head and tail pulleys 30 and 31, respectively. A conveyor belt 32 is trained about the pulleys 30 and 31 and operates therebetween over a series of spaced troughing idlers (not shown) in a manner well known in the art. The head pulley 30 is used to drive the belt and may, in turn, be driven by the engine 24 or a separate power source in a conventional manner. It is also known to drive the belt through the tail pulley 31.
The head pulley 30 is positioned over the charging hopper 25 and the conveyor extends forwardly over the top of the mixer 11 and curves downwardly over the head end of the drum l4 and engine 24. The forward charging end of the conveyor 13 lies just forwardly of the trailer chassis l8 and is provided with a receiving hopper 33 disposed sufficiently low to be reached by the chute C of a truck mixer or the like.
The conveyor 13 is secured in position at its head end by attachment of the side rails 29 to extensions 34 of the upright frame members 16 on either side of the drum. Similar vertical extensions 35 extending upwardly from the pedestal l5 rigidly support the opposite end of the conveyor. The conveyor is preferably demountably secured to the extensions 34 and 35 for reasons which will be set forth below.
The semitrailer 12 is provided with tandem dual wheels 36 at the rear and a kingpin or fifth wheel 37 at the forward end for towing attachment to a truck tractor (not shown). The forward end of the trailer may also be provided with suitable legs 38 or other means of stabilization and support when disconnected from the towing vehicle.
In operation, the portable concrete-holding mixer 10 is towed to a construction site and positioned where the receiving hopper 33 can be most readily reached by the chute C of a truck mixer delivering concrete to the job site. Ideally, the hopper 33 will be positioned such that the truck mixers can move directly to and away from the point of discharge without the necessity of backing or otherwise maneuvering into position to reach it.
The discharge end of the holding mixer 10 is conveniently located to be reached by the bucket B or other means adapted to receive concrete from the discharge chute 28. The chute 28 may, of course, be provided with one or more extensionv sections, as required, and the pivotability of the chute may, in some instances, make direct final placement therefrom feasible.
. A truck mixer can discharge its entire load of concrete into the hopper 33 in one continuous operation. The conveyor belt 32 carries the concrete to the charging hopper 25 through which it is funneled to the interior of the drum 14. The drum may be rotating in either the direction for holding and mixing or the direction for discharge depending on the immediate requirements of concrete for placement. If the former, the concrete will be moved forwardly by the spiral blade 26 and accumulated in the larger and lower forward end of the drum 14. The drum capacity is preferably greater than the capacity of the average truck mixer delivering concrete, with 9 to 10 cubic yards being a practical minimum capacity. In this manner, a halt or temporary delay in pouring will not effect any corresponding delay in the discharge of concrete from the truck mixer.
If the drum 14 is rotated in the opposite direction, the blade 26 will move the concrete upwardly and rearwardly to discharge over the lip 27 surrounding the open drum end. The rate of discharge may be varied by control of the speed of rotation in a known manner. A supply of concrete in the drum l4 ensures the availability of concrete despite a temporary halt in the supply thereto, which may be occasioned by the delivery vehicles being delayed en route or at the construction site.
The receiving end 41 of the conveyor 13, including the receiving hopper 33, which extends beyond the forward end of the trailer 12 is retractable for transport or to allow truck mixers or other equipment to move past as may be required for effective operation in a confined area. The receiving end may be attached by a pivot 42 to the remainder of the conveyor 13, and may include a power-operated retracting means (not shown). A substantial portion of the conveyor, including the siderails and idlers, is, however, preferably constructed of aluminum or other lightweight materials, whereby manual retraction of the receiving end 41 is easily accomplished. The receiving end may also be designed to telescope into the remaining portion to effect retraction, in a manner known in the art.
The entire conveyor 13 is adapted to be demounted from its operative position secured to the mixer frame extensions 34 and 35. The conveyor siderails 29 may be attached to the frame extensions 34 and 35 by means of pinned connections 44 and 45, respectively, for rapid demounting. With the conveyor removed, the unit is a conventional semitrailer-mounted transit mixer and may be operated as such without any further modification.
Alternately, a slat conveyor or a screw conveyor, of a type well known and commonly used to convey concrete, could be used in place of the belt conveyor 13. The mixer 11 and conveyor 13 could, as an alternate embodiment, be mounted on a standard chassis-cab unit, as mobile concrete mixers most often are. A half-ca would be required for this embodiment to provide space for the descending forward portion of the conveyor.
1. In combination with a concrete mixing drum rotatable about an inclined axis with an opening at its upper end for charging and discharging materials, said drum being provided with inwardly extending spiral blades terminating at said opening and a charging hopper feeding into the central portion of the drum opening interiorly of said spiral blades;
an inclined belt conveyor arranged over said drum with its inclination in the same direction as the axis of said drum, said belt conveyor having a head pulley arranged over said hopper to cause material conveyed by the belt to discharge into the hopper, and a tail pulley conveniently low to the ground to enable charging of the belt conveyor by a similar concrete mixer mounted on a delivery truck, or by other means;
and means for rotating the drum and driving the belt conveyor so that materials in the drum are discharged through the opening simultaneously with the feeding of material by the conveyor to the drum;
whereby the drum may be used to accommodate surges in supply of concrete in excess of the desired rate of discharge of concrete from the mixing drum.
2. A portable concrete mixer for temporary holding of mixed concrete delivered to a job site which comprises: a transportable frame, a power driven inclined conveyor carried by said frame and having a lower hopper disposed to receive mixed concrete from a delivery vehicle and having an upper charging hopper, an inclined discharge chute carried by said frame so that its upper end remains effectively positioned beneath said hopper and so that its lower end may be variously positioned to deliver by gravity the concrete into a receiving bucket or the like positioned within the reach of the chute, and an inclined-axis power-driven spiral-bladed concrete mixing drum carried by said frame and having its charging and discharging opening disposed to receive the concrete discharging from said charging hopper and to deliver the same to said chute as required whereby to provide temporary storage in the order of one full load of a typical delivery vehicle so that the uninterrupted supply of concrete to the job site is materially assured.
3. A portable concrete mixer unit for temporary holding of mixed concrete delivered to a job site which comprises: a vehicle including a frame, wheels for transport to and ground-stabilizing legs for stationary positioning at the job site, a concrete mixing drum supported by said frame for rotation on an inclined axis and having an upper open end at one end of the vehicle, said drum internally having spiral blades which extend to said drum opening and define a smaller central charging opening, power means carried vby the vehicle and connected to said drum to rotate the latter in one direction which causes the blades to push the drum contents to the lower closed end thereof and in the other direction to push the contents toward and out of the upper open end thereof, a charging hopper for said drum carried by said frame and having its spout extending into said smaller central opening of the drum, an inclined power-driven conveyor carried by said vehicle frame and having a receiving hopper disposed at the other end of the vehicle to receive mixed concrete as from a delivery truck, said conveyor extending longitudinally over said drum and having its discharge trajectory directed into said charging hopper, and an inclined discharge chute pivotally supported by said frame on a vertical axis beneath said charging hopper and drum opening so that its upper end remains positioned to receive concrete therefrom and so that its lower end may be variously positioned to deliver by gravity the concrete into a receiving bucket or the like positioned within reach of the chute.
4. The unit of claim 3 wherein the conveyor includes parallel frame extensions which support the receiving hopper beyond the end of the vehicle frame and said receiving hopper and the projecting portion of the conveyor are retractable as required for transport or to allow trucks to move past the end of the unit.
5. The invention of claim 3 wherein the vehicle comprises a conventional semitrailer.
6. The invention of claim 3 wherein the conveyor is demountable from said vehicle frame such that the unit may be used to deliver concrete as in the manner of a truck mixer.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2357583 *||Jul 29, 1942||Sep 5, 1944||John S Franco||System and apparatus for handling concrete|
|US3038705 *||Nov 16, 1959||Jun 12, 1962||Machinery Company Const||Drum for truck mounted concrete mixers|
|US3185450 *||Oct 7, 1963||May 25, 1965||Duecy George P||Cement transporting and placing machine|
|US3526392 *||May 20, 1968||Sep 1, 1970||Rex Chainbelt Inc||Method of hauling and mixing concrete|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US3866889 *||Aug 16, 1972||Feb 18, 1975||Stowell Ind Inc||Mobile conveyor system|
|US3888467 *||Sep 27, 1973||Jun 10, 1975||Sheets Charles W||Concrete holding and mixing assembly and method of transporting and distributing concrete|
|US3901485 *||May 16, 1973||Aug 26, 1975||Schwing Gerhard||Concrete delivery units|
|US3958304 *||Apr 9, 1973||May 25, 1976||Iowa Beef Processors, Inc.||Machine for washing tripe|
|US4441820 *||Sep 27, 1982||Apr 10, 1984||Maxon Industries, Inc.||Concrete mix surge bin|
|US5785419 *||Oct 10, 1995||Jul 28, 1998||Mckelvey; Paul A.||Lightweight building material and method of construction of cast-in-place structures|
|US8007697 *||Sep 8, 2005||Aug 30, 2011||Luca Toncelli||Method for manufacturing articles in the form of thin slabs of composite stone and resultant articles|
|US20080111267 *||Sep 8, 2005||May 15, 2008||Luca Toncelli||Method for Manufacturing Articles in the Form of Thin Slabs of Composite Stone and Resultant Articles|
|U.S. Classification||366/27, 366/59|
|International Classification||B28C5/42, B28C5/00|
|Cooperative Classification||B28C5/4234, B28C5/4241|
|European Classification||B28C5/42A3, B28C5/42A3B2|
|Jun 7, 1982||AS||Assignment|
Owner name: REXWORKS, INC., A CORP. OF DE.
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:REXNORD INC.;REEL/FRAME:004000/0737
Effective date: 19820423