US3915439A - Non-tilt mixer and blade means therefor - Google Patents

Abstract

A non-tilt mixer comprises a drum supported on and reversely rotatable about its horizontal axis (for mixing and then discharge) by means of pneumatically-tired wheels. The drum comprises a cylindrical center section and conical end sections and has an inlet opening at one end and a discharge opening at its other end. The drum is provided on its interior with a plurality of flat mixer blades secured to the inside of the cylindrical center section and with a plurality of curved or scoop-like discharge blades secured to the inside of the conical section at the discharge end of the drum. Each discharge blade extends between and partially overlaps an adjacent pair of mixer blades. Each discharge blade defines a scoop or chute which is operable when the drum rotates in the discharge direction to discharge through the discharge opening of the drum. The discharge blades are arranged and connected so that the several chutes converge and discharge at the center of the discharge opening.

Description

United States Patent [1 1 Albin et a1.

[4 1 Oct. 28, 1975 NON-TILT MIXER AND BLADE MEANS THEREFOR [75] Inventors: Max D. Albin; James R. Clabaugh,

both of Urbana; Luis G. Manero, Champaign, all of 111.

[73] Assignee: Koehring Company, Milwaukee,

Wis.

[22] Filed: May 28, 1974 [21] Appl. No.: 473,330

[52] US. Cl 259/177 R; 259/3; 259/30 [51] Int. Cl. B28C 5/20 [58] Field of Search 259/177- R, 3, 30,57, 175,

FOREIGN PATENTS OR APPLICATIONS Belgium 259/177 Attorney, Agent, or FirmAndrew .1. Beck [5 7 ABSTRACT A non-tilt mixer comprises a drum supported on and reversely rotatable about its horizontal axis (for mixing and then discharge) by means of pneumaticallytired wheels. The drum comprises a cylindrical center section and conical end sections and has an inlet opening at one end and a discharge opening at its other end. The drum is provided on its interior with a plurality of flat mixer blades secured to the inside of the cylindrical center section and with a plurality of curved or scoop-like discharge blades secured to the inside of the conical section at the discharge end of the drum. Each discharge blade extends between and partially overlaps an adjacent pair of mixer blades. Each discharge blade defines a scoop or chute which is operable when the drum rotates in the discharge direction to discharge through the discharge opening of the drum. The discharge blades are arranged and connected so that the several chutes converge and discharge at the center of the discharge opening.

5 Claims, 12 Drawing Figures US. Patent Oct.28, 1975 Sheet10f4 3,915,439

U.S. Patent Oct.28, 1975 Sheet 2 of4 3,915,439

US. Patent Oct. 28, 1975 Sheet 3 of4 3,915,439

US. Patent' Oct. 28, 1975 Sheet 4 of4 3,915,439

FIG.1O

NON-TILT MIXER AND BLADE MEANS THEREFOR BACKGROUND OF THE INVENTION 1. Field of Use This invention relates generally to non-tilt reversely rotatable mixers, such as are usedwith concrete batch plants, and particularly to mixing and discharge blade means inthe drum thereof.

2. Description of the Prior Art U.S. Pat. No. 3,016,232, issued Jan. 9, 1962 to Domenighetti for Mixer Driven and Supported by Wheels of Flexible Material, discloses a mixer having a drum reversely rotatable about a horizontal axis, inlet and discharge openings in conical end sections at opposite ends of the drum, two spaced apart roller assemblies including pneumatic tired wheels for supporting the drum and for rotating the drum in opposite directions (one way for mixing and the opposite way for discharge), means for driving the shaft of both roller assemblies, and a pair of axially spaced apart auxiliary rollers acting on the drum to prevent axial drum movement. The prior art also discloses a wide variety of blade configurations and arrangements in mixers of various kinds. For example, Pat. No. 3,258,253 shows a drum type mixer (rotatable in one direction only) having a set of bracket-supported mixer blades near the inlet end of the drum, which blades are angularly offset from the axis of drum rotation. Pat. No. 3,258,253 also shows a set of bucket blades near the outlet end of the drum. British Patent 328,895 shows flat blades near the inlet and curved blades near the outlet of a drum. However, the prior art does not disclose blade shapes or blade arrangements of the same type as in the subject mixer.

SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a non-tilt concrete mixer for use, for example, with a concrete batch plant and comprising a horizontally disposed reversely rotatable drum and means for driving or rotating the drum in opposite directions about its horizontal axis. The drum, which comprises a generally cylindrical center section and conical end sections with an inlet opening in the conical section at one end and a discharge opening in the conical section at the other end, is supported on and reversably drivable or rotatable about its horizontal axis (for mixing and discharge purposes) by means of a support and drive assembly. The assembly comprises a pair of parallel spaced apart rotatable shafts (at least one of which is driven by an electric or hydraulic motor) and each shaft has two spaced apart sets of pneumatically tired wheels mounted thereon for rotation therewith. Each set comprises one or more wheels which engage the exterior surface of the cylindrical section of the drum and each set nearest the drum inlet end comprises a greater number of wheels than the set nearest the drum outlet end. Roller means engage opposite ends of the cylindrical center section of the drum to prevent axial movement of the drum as it rotates. The generally conical inlet and outlet end sections of the drum are provided with inlet and discharge openings at the centers of the conical inlet and outlet end sections, respectively. The drum rotates about its axis in one direction for mixing purposes and in an opposite direction 'for discharge purposes. A plurality (preferably three or four) or spaced apart mixing blades are mounted on the inside of the cylindrical section of the drum. Each mixer blade is flat and is supported on a pair of spaced apart brackets on a cylindrical mid-portion of the drum, with its lower edge spaced from the drum wall and with its leading edge offset from the axis of drum rotation in the mixing direction so that its planar surfaces define an angle of about 12 with the drum axis. A plurality (preferably three or four) of spaced apart discharge blades are mounted on the inside of the conical discharge end section of the drum. Each discharge blade is disposed intermediately of an adjacent pair of mixer blades and extends partially therebetween in overlapping relationship thereto. Each discharge blade, which is preferably fabricated of three blade sections, is scoop-like and defines a chute dischargeable through the discharge opening of the drum. The plurality of discharge blades are arranged and connected to the drum and to each other so that all of the chutes converge near the center of said discharge opening. The discharge blades operate to discharge material being mixed in the drum only when the drum rotates in one direction.

A mixer having blades and blade arrangements in accordance with the invention affords several advantages over prior art arrangements. For example, the converging or concentric arrangement of the several discharge chutes concentrates the mix being discharged into a smaller stream, thereby reducing spillage and waste as the mixer discharges. The overlapped arrangement of the mixer and discharge blades causes the mixer blades to feed the discharge blades during discharge rotation. The discharge blade arrangement is extremely strong and can handle heavy loads, as the blades are supported not only on the drum but by each other. The mixer and discharge blades are relatively easy and inexpensive to fabricate, install and replace when worn. Furthermore, the discharge blades, although defining scoops or chutes of a complex shape which facilitates neat and complete discharge from the drum, are actually formed of flat blade sections cut from sheet metal and do not require complex dies or special presses during fabrication.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of a cement mixer in accordance with the invention shown associated with portions of a concrete batch plant;

FIG. 2 is an elevation view of the exterior of the discharge end of the mixer shown in FIG. 1 with parts broken away to show details;

FIG. 3 is an enlarged view, partly in section, of the mixer drum taken on line 33 of FIG. 2;

FIG. 4 is a view of the interior of the discharge end of the mixer drum taken on line 44 of FIG. 3;

FIG. 5 is an enlarged view similar to FIG. 4 of the discharge end of another embodiment of four-bladed mixer drum in accordance with the invention;

FIG. 6 is an enlarged view similar to FIG. 2 of the blade arrangement shown in FIG. 5;

FIG. 7 is an enlarged perspective view taken from the discharge end of the drum and showing one discharge blade of the mixer shown in FIGS. 1, 2, 3 and 4;

FIG. 8 is a plan view of a blank for one blade section for the discharge blade shown in FIG. 7 prior to bending and forming thereof;

FIG. 9 is an end view of the blade taken on line 9-9 of FIG. 8 after it is bent to shape;

FIG. is a plan view of a first fillet plate shown in FIG. 7;

FIG. 11 is a plan view of a second fillet plate shown in FIG. 7; and

FIG. 12 is a perspective view. similar to FIG. 7, of one discharge blade assembly comprising the blade and fillets shown in FIGS. 7 through 11.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, there is provided a nontilt concrete mixer 10 for use, for example, with a concrete batch plant which, for example, includes a feed hopper 11 and a discharge chute 12. Mixer 10 comprises a horizontally disposed reversely rotatable drum 14 and means for driving or rotating the drum in opposite directions about its horizontal axis 15. The drum 14, which comprises a generally cylindrical center section 16 and conical end sections 17 and 18, with an inlet opening 20 in the conical section at the drum inlet end and a discharge opening 21 in the conical section at the drum discharge end, is supported on reversably drivable or rotatable about its horizontal axis 15 (in the direction of arrow 22 for mixing and in the direction of arrow 23 for discharge) by means of a support and drive assembly. The assembly comprises a pair or paral lel spaced apart rotatable shafts supported on a frame 24 as by bearings 31. At least one shaft 25 is driven by an electric or hydraulic motor 26, and each shaft 25 has two spaced apart sets 28 and 29 of pneumatically tired wheels 27 mounted thereon for rotation therewith. Each set 28 and 29 comprises one or more wheels 27 which engage the exterior surface of the cylindrical section of the drum 14 and each set 28 nearest the drum inlet end comprises a greater number of wheels than the set 29 nearest the drum outlet end. Roller means 30 engage opposite ends of the cylindrical center section 16 of the drum 14 to prevent axial movement of the drum as it rotates. The generally conical inlet and outlet end sections 17 and 18 of the drum 14 are provided with inlet and discharge openings 20 and 21, respectively, at the centers of the conical inlet and outlet end sections 17 and 18, respectively. The drum 14 rotates about its axis 15 in one direction (arrow 22) for mixing purposes and in an opposite direction (arrow 23) for discharge purposes. As FIGS. 3 and 4 show, a plurality (three) of spaced apart mixing blades 34 are mounted on the inside of the cylindrical section 16 of the drum 14. Each mixer blade 34 is flat and is supported as by welding, on a pair of spaced apart brackets 37 which are connected as by welding to the inside of cylindrical section 16 of the drum 14, with the lower edge 38 of each blade 34 being spaced from the drum wall and with the leading edge 39 of each blade 34 being offset from the axis 15 of drum rotation in the mixing direction so that the planar surfaces 42 of blade 34 define an angle of about 12 with the drum axis. as FIG. 1 shows. As FIGS. 2, 3 and 4 show, a plurality (three) of spaced apart discharge blades 50 are mounted on the inside of the conical discharge end section 18 of the drum 14. Each discharge blade 50 is disposed intermediately of an adjacent pair of mixer blades 34 and extends partially therebetween in overlapping relationship thereto, as FIG. 3 shows. Each discharge blade 50, as FIGS. 7 through 12 show, is preferably fabricated of three blade sections, 52, 54, 56, is scoop-like and defines a chute 60 dischargeable through the discharge opening 21 of the drum 14. The

plurality of discharge blades 50 are arranged and con- 4 nected to the drum 14 and to each other so that all of the chutes 60 converge near the center of discharge opening 21. The discharge blades operate to discharge material being mixed in the drum only when the drum rotates in one direction, i.e. in the direction of arrow 23.

The converging or concentric arrangement of the several discharge chutes 60 concentrates the mix being discharged through opening 21 into a smaller stream, thereby reducing the possibility of spillage and waste as the mixer 10 discharges into chute 12. The overlapped arrangement of the mixer blades 34 and the discharge blades 50 causes the mixer blades 34 to feed the discharge blades 50 during discharge rotation in the direction of arrow 23. The discharge blade arrangement is extremely strong and can handle heavy loads, as the blades 50 are supported not only on the drum 14, as by welding at 61, but by each other, as by welding at 75. The mixer blades and the discharge blades 50 are relatively easy and inexpensive to fabricate, install and replace when worn. Furthermore, the discharge blades 50, although defining scoops or chutes 60 of a complex shape which facilitates neat and complete discharge from the drum 14, are each actually formed of blade sections 52, 54 and 56 cut from sheet metal and initially flat and, therefore, do not require complex dies or special presses during fabrication.

Referring to FIGS. 7 through 12, each discharge blade 50 comprises a main blade section 52 and fillet means formed of two flat blade sections 54 and 56 joined by welding as at 73. Main blade section 52, which is initially flat, is bent along fold lines 66 and 67 and cooperates with the fillet means to define side walls of the chute 60. Main blade section 52 has an edge 61 connected to the inside surface of drum 14 as by welding at 62. Edge 61 comprises two curved edge portions 61A and 61B which conform to the shapes of conical drum section 18 and cylindrical drum section 16, respectively. Main blade section 52 also has a free edge 64. The fillet means is connected, as by welding at 63 and 65, to and between the inside surface of drum l4 and the scooping surface of main blade section 52. Section 54 of the fillet has an edge 69 conforming to the shape of conical drum section 18. Section 56 of the fillet has an edge 68 conforming to the shape of cylindrical drum section 16. Main blade section 52 of discharge blade 50 is provided with a discharge end 74 or edge which is connected as by welding at 75 to and between the corresponding edges of a pair of adjacent discharge blades 50.

Referring to FIGS. 5 and 6, there is shown another embodiment of a mixer 10A in accordance with the invention having a drum 14A similar in all respects and in mode of operation to drum 14 hereinbefore described, except that drum 14A comprises four mixer blades 34A and four discharge blades 50A and is especially well adapted for handling a larger quantity of mix than mixer 10 hereinbefore described, i.e., for example, 2 cubic yards as compared to 1 cubic yard. Each mixer blade 50A comprises a main blade section 52A, and a two blade section 54A and 56A forming a fillet which cooperates with section 52A to define a chute 60A.

OPERATION Mixer 10 operates in the following manner. it being understood that mixer 10A would operate in substantially the same manner. A batch of cement and aggregate (including sand) and necessary water is deposited in chute 11 and from there through opening 20 into the interior of drum 14. Drum 14 rotates in the mixing direction, i.e. in the direction of arrow 22, by means of motor 26 which drives shaft 25 to cause rotation of the wheels 27 on the driven shaft in the appropriate direction. Since the load in drum 14 is heaviest at the inlet end of the drum, it is preferable to provide a set of wheels comprising a greater number of wheels 27 than at the opposite end of the drum. Preferably, drum 14 is rotating in the mixing direction as the load of mix is being supplied thereto. As drum 14 rotates in the mixing direction mixing is accomplished by means of the mixing blades 34. The space between the lower edge 38 of each mixing blade 34 enables passage of water and the slurry as the drum rotates. Since the drum 14 is rotating in the mixing direction (arrow 22) the chutes 60 defined by the discharge blades 50 are unable to scoop up and discharge any of the mix. After drum 14 has been rotated sufficiently to effect proper mixing, the

direction of drum rotation is reversed so that the drum rotates in the discharge direction (arrow 23) to effect discharge of the mix through the chutes 60 and through discharge I opening 21 into the discharge chute .12. When the drum 14 is rotating in the discharge direction angular disposition of the mixing blades 34, each of which extends between and overlaps a pair of adjacent discharge blades 50, causes mix to be channelled toward the chutes 60 defined by the discharge blades 50. In addition, the discharge blades 50 tend to scoop up mix from the bottom of the drum 14. The mix being scooped up by each chute 60 is caused by gravity to slide downwardly and outwardly through discharge opening 21 in drum 14 as the chute 60 rotates from the downward disposition shown in FIG. 3 and past a horizontal position toward the sloped position shown in the uppermost portion of FIG. 3. The arrangement and configuration of the mixing blades 34 and the discharge blades 50 is such that substantially all of the mix contained in drum 14 is fed outwardly of the drum through discharge opening 21 by means of the discharge blades 50. As hereinbefore explained, a portion of each discharge blade 50 extends into and is secured to the cylindrical portion 16 of drum 14. In this manner the drum is completely emptied during the discharge process. As hereinbefore explained, the drum 14A of mixer A operates in substantially the same manner as mixer 10. However, since drum 10A has a larger total capacity than mixer 10 it is preferable that each mixer blade 34A and each discharge blade 50A handle a proportionately larger amount of the total mix. It is to be understood further that the mixer drum 14A is mounted and driven in the same manner as drum 14.

We claim:

1. In a mixer: a drum rotatable about a horizontal axis and comprising a cylindrical center section and end sections, one end section being provided with an inlet opening and the other end section being a conical discharge section and provided with a centrally located discharge opening, means for supporting and for rotating said drum about its axis in one direction for mixing and in an opposite direction for discharge, a plurality of spaced apart flat mixing blades mounted on but spaced from the inside of said cylindrical section of said drum, each mixing blade being angularly offset from the axis of drum rotation, and a plurality of spaced apart discharge blades mounted on the inside of said conical discharge section of said drum, each discharge blade being disposed intermediately of an adjacent pair of mixer blades and extending partially therebetween in overlapping relationship thereto, each discharge blade defining a chute discharge through said discharge opening of said drum, each chute being located on the side of the blade in the direction in whic said drum rotates during discharge, each of said plurality of discharge blades being arranged and connected to the inside of said conical discharge section and to adjacent discharge blades so that all of said chutes converge near the center of said discharge opening, each discharge blade comprising a main blade section and fillet means, said main blade section having one edge connected to said conical discharge section and a bent free edge defining a side of said chute, said fillet means being connected to and between said conical discharge section and said main blade section and defining another side of said chute, each main blade section having a discharge end connected to the discharge ends of the adjacent discharge blades.

2. A mixer according to claim 1 wherein each of said fillet means comprises two blade sections which are connected to each other.

3. A mixer according to claim 2 wherein said two blade sections are flat and wherein siad main blade section is generally fiat but is provided with an upturned free edge.

4. A mixer according to claim 1 wherein said means for supporting and rotating said drum comprises a pair of horizontally spaced apart shafts, a pair of spaced apart sets of pneumatically-tired wheels on each shaft, each set comprising at least one of said wheels, and means for selectively driving at least one set of wheels on at least one of said shafts to effect rotation of said drum in a desired direction.

5. A mixer according to claim 4 wherein each set of wheels closest to said inlet opening of said drum comprises a greater number of wheels than the set of wheels closest to said discharge opening.

Claims (5)

1. In a mixer: a drum rotatable about a horizontal axis and comprising a cylindrical center section and end sections, one end section being provided with an inlet opening and the other end section being a conical discharge section and provided with a centrally located discharge opening, means for supporting and for rotating said drum about its axis in one direction for mixing and in an opposite direction for discharge, a plurality of spaced apart flat mixing blades mounted on but spaced from the inside of said cylindrical section of said drum, each mixing blade being angularly offset from the axis of drum rotation, and a plurality of spaced apart discharge blades mounted on the inside of said conical discharge section of said drum, each discharge blade being disposed intermediately of an adjacent pair of mixer blades and extending partially therebetween in overlapping relationship thereto, each discharge blade defining a chute dischargeable through said discharge opening of said drum, each chute being located on the side of the blade in the direction in which said drum rotates during discharge, each of said plurality of discharge blades being arranged and connected to the inside of said conical discharge section and to adjacent discharge blades so that all of said chutes converge near the center of said discharge opening, each discharge blade comprising a main blade section and fillet means, said main blade section having one edge connected to said conical discharge section and a bent free edge defining a side of said chute, said fillet means being connected to and between said conical discharge section and said main blade section and defining another side of said chute, each main blade section having a discharge end connected to the dIscharge ends of the adjacent discharge blades.

2. A mixer according to claim 1 wherein each of said fillet means comprises two blade sections which are connected to each other.

3. A mixer according to claim 2 wherein said two blade sections are flat and wherein said main blade section is generally flat but is provided with an upturned free edge.

4. A mixer according to claim 1 wherein said means for supporting and rotating said drum comprises a pair of horizontally spaced apart shafts, a pair of spaced apart sets of pneumatically-tired wheels on each shaft, each set comprising at least one of said wheels, and means for selectively driving at least one set of wheels on at least one of said shafts to effect rotation of said drum in a desired direction.

5. A mixer according to claim 4 wherein each set of wheels closest to said inlet opening of said drum comprises a greater number of wheels than the set of wheels closest to said discharge opening.

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