United States Patent 3580550

A bladed mixing rotor particularly for viscous liquids having plural radial blades projecting from a central hub. Each blade has a first recess in its lower surface adjacent the hub and a second recess in its top surface outwardly of the first recess. Two inclined pumping surfaces are thus formed on each blade, the pumping surfaces being reversely inclined.

Application Number:
Publication Date:
Filing Date:
Primary Class:
Other Classes:
366/312, 366/343, 366/605, 416/237
International Classes:
B01F7/00; B01F15/00; (IPC1-7): B01F7/20
Field of Search:
259/8,23,24,66,67,107,108,134,135 416
View Patent Images:
US Patent References:
3365176Agitator apparatus1968-01-23Christensen

Primary Examiner:
Roberts, Edward L.
I claim

1. A mixing rotor for viscous liquids comprising a center hub portion adapted for connection to the rotating drive shaft normal to the plane of the rotor, and plural circumferentially spaced radial mixing blades carried by and extending from said hub portion, each mixing blade having a first recess in its lower surface immediately outwardly of the hub portion and forming on the blade an inclined face converging with the top face of the rotor to form a first leading edge portion on the blade, each blade having a second recess formed in its top surface radially outwardly of the first recess and producing a second inclined face reverse to the inclination of the first-named inclined face and converging with the lower surface of the rotor to produce a second leading edge portion on the blade radially outwardly of the first leading edge portion and offset therefrom by a distance substantially equal to the thickness of the rotor, the second leading edge portion of the blade extending substantially to the outer end of the blade, and projections on the outer tips of the rotor blades extending somewhat in advance of the second leading edge portions and said second recesses including curved wall portions which blend smoothly into said projections.

2. A mixing rotor as defined by claim 1, and terminal scraping edges on said projections normal to the opposite main surfaces of the rotor and extending entirely between said main surfaces.

3. A mixing rotor as defined by claim 1, and wherein the terminal ends of the mixing blades are curved substantially concentric with the center of the rotor, said curved ends constituting the exterior sides of said projections.

The objective of the invention is to improve upon the prior art by the provision of a more efficient bladed mixing rotor capable of wide usage in the thorough mixing of viscous liquids and, in particular, paints. The rotor is also capable of use in the kitchen, such as in a blender or stirrer. The rotor may be constructed of various materials ranging from metals to plastics depending upon the particular usage thereof.


FIG. 1 is a side elevation, partly in section, illustrating the construction and operation of mixing apparatus embodying the invention.

FIG. 2 is a horizontal section taken on line 2-2 of FIG. 1.

FIG. 3 is a bottom plan view of the mixing rotor.

FIGS. 4 and 5 are enlarged fragmentary transverse vertical sections taken, respectively, on lines 4-4 and 5-5 of FIG. 2 through one blade of the mixing rotor.


Referring to the drawings in detail, wherein like numerals designate like parts, the numeral 10 designates a cylindrical container, such as a 5 -gallon conventional paint can. The size of the container is immaterial and may vary through a wide range, the mixing apparatus being sized to accommodate various containers.

The numeral 11 designates a mixing rotor in its entirety constituting the heart of the invention and this rotor is adapted to be formed of cast aluminum, molded plastic or various materials depending upon its usage. The mixing rotor 11 has flat parallel top and bottom faces 12 and 13 and is sufficiently thick between these faces to be rigid and to allow the formation of certain recesses, to be described, which produce the desired mixing effect on the liquid in the container 10.

The rotor 11 comprises a central circular disc or hub portion 14 having a central opening 15 for the reception of the lower end of a rotary vertical drive shaft 16, as shown. Preferably three circumferentially equidistantly spaced mixing blades 17 extend radially from the hub portion 14 and are of equal length and of the same thickness between the faces 12 and 13 as the remainder of the rotor. As shown in FIGS. 2 and 3, the blades 17 are quite wide circumferentially in comparison to their thickness.

The blades 17 are provided in their lower faces immediately outwardly of hub portion 14 with recesses 18 whose faces are flat and inclined or diagonal with relation to the top and bottom faces 12 and 13. The recesses 18 converge with the upper flat face 12 to produce leading edge portions 19 on the rotor blades 17 extending from the hub portion 14 radially outwardly to approximately the longitudinal centers of the blades 17, FIG. 3. The angularity or inclination of the recesses 18 may vary. In the drawings, the recesses intersect the lower flat face 13 as at 20 approximately at the transverse center of each blade 17. In some cases, the angle of the recess 18 may be less steep so that the recess will intersect the surface 13 closer to the rear edge 21 of the blade. The term "leading edge" as used in connection with the portion 19 is in reference to the direction of rotation of the mixing rotor, as shown by the arrows in FIGS. 2 and 4.

Radially outwardly of the recesses 18, the blades 17 are similarly recessed in their top faces as shown at 22, FIGS. 2 and 5. The surfaces of the recesses 22 are inclined reversely with respect to the inner recesses 18 and preferably have the same slope or angularity as the recesses 18 although in the opposite direction. The inclined faces of recesses 22 converge with the bottom flat surface 13 of the rotor to form radial leading edge portions 23 on the outer extremities of the blades 17. As clearly shown in FIG. 1, short diagonal leading edge portions 24 connect the edge portions 19 and 23 of each blade 17 where the reversely beveled recesses meet at approximately the longitudinal center of the blade. The rear edge 21 of each blade is straight and normal to the faces 12 and 13.

The outer tip of each blade 17 is curved as at 25 preferably on an arc concentric with the hub portion 13 and central opening 15. A leading projection 26 is formed on the outer tip of each blade extending in the direction of rotation and presenting a scraping edge 27, FIG. 1, extending across the full thickness of the rotor. As shown best in FIG. 2, the recesses 22 blend smoothly into the projections 26 by means of curved recess faces 28 blending into the major recesses 22 without interruption. As shown in FIG. 2, the curved tips 25 pass close to the sidewall of the container 10 during operation and the clearance distance may be as little as one-sixteenth of an inch in the case of a 5 -gallon paint can. The edges 27 of tips 26 may clear the wall of the paint can by approximately one-eighth of an inch, the tips or projections 26 extending inwardly somewhat in the radial direction.

As stated, the mixing rotor opening 15 receives a lower end portion of shaft 16 and the rotor 11 is clamped to the shaft 16 for rotation therewith by a bottom cap nut 29 which may engage the bottom wall of the container and a coacting upper nut 30. The drive shaft 16 is connected with and driven by the chuck 31 of a conventional electrical hand drill or the like. Preferably, the shaft 16 extends slidably through a guide sleeve 32 at the center of a spider support 33 which may rest upon the top flange of the can or container, as shown. This arrangement aids the user in raising and lowering the mixing rotor within the container 10 during its rotation to more thoroughly stir the liquid contents. The described rotor blade construction provides a unique pumping and swirling effect upon the liquid in the upward and downward direction as indicated by the diagram arrows in FIG. 1. The outermost recesses 22 in the top surface of the rotor pump the liquid upwardly near the periphery of the container while the interior reversely slanted recesses 18 draw the liquid downwardly substantially at the center of the liquid mass. The tips 26 and edges 27 tend to draw any solid material inwardly and away from the sidewall of the container for entrainment in the pumping stream produced by the recesses 18 and 22.

It is thought that the operation and the advantages of the invention should now be clearly understood by those skilled in the art without any further description.

It is to be understood that the form of the invention herewith shown and described is to be taken as a preferred example of the same, and that various changes in the shape, size and arrangement of parts may be resorted to, without departing from the spirit of the invention or scope of the subjoined claims.