Title:
CONCRETE AND THE LIKE MIXER
United States Patent 3580551


Abstract:
A concrete or the like mixer comprises an open-topped main mixing container and a premixer disposed above the main mixing container and having a circular bottom wall rotated about a vertical axis and normally frictionally engaging the lower part of a cylindrical sidewall forming a premixing container together with said bottom wall. In order to discharge the contents of the premixer into the main mixing container, the bottom and sidewalls of the premixer are temporarily disengaged, to provide a peripheral annular discharge passage.



Inventors:
Hammann, Heinz (Speyerdorf, DT)
Dick, Werner (Eisingen, DT)
Application Number:
04/850112
Publication Date:
05/25/1971
Filing Date:
08/14/1969
Assignee:
LICO AG.
Primary Class:
Other Classes:
366/42
International Classes:
B01F15/00; B28C5/08; B28C5/28; (IPC1-7): B28C7/16
Field of Search:
259/30,31,32,33,34,50,152,169,170,178 222
View Patent Images:
US Patent References:
1447125Concrete mixer1923-02-27Dunn et al.



Primary Examiner:
Scheel, Walter A.
Assistant Examiner:
Cantor, Alan I.
Claims:
We claim

1. A concrete and the like mixer comprising in combination:

2. a main mixer including an open-topped main mixing container, and

3. a premixer disposed above said main mixer and comprised of

4. A mixer as claimed in claim 1, wherein said bottom wall has a flat conical shape.

5. A mixer as claimed in claim 1, wherein said sidewall has an inturned lower portion engaged by the edge of said bottom wall in the normal position and acting as a discharge chute for the contents of said premixer in the discharge position thereof.

6. A mixer as claimed in claim 3, wherein said last means is comprised of means to temporarily raise the bottom wall of said premixer.

7. A mixer as claimed in claim 3, wherein said last means is comprised of means to temporarily lower the sidewall of said premixer.

8. A mixer as claimed in claim 1, including means to feed the aggregates to be mixed to said premixing container.

9. A mixer as claimed in claim 1, wherein said main mixing container is of cylindrical shape concentric with said premixer and said sidewall is freely rotatively peripherally supported by the upper edge of said main mixing container.

10. A mixer as claimed in claim 1, wherein said main mixing container is of cylindrical shape concentric with said premixer and said sidewall of said premixer is freely rotatively peripherally and axially displaceably supported upon the upper edge of said main mixing container.

11. A mixer as claimed in claim 1, wherein said sidewall of said premixer has an inturned lower portion engaged by the edge of said bottom wall in the normal position and acting as a discharge chute for the contents of the premixer in the discharge position thereof, said main mixing container is of cylindrical shape concentric with said premixer and having an upper flange, and said sidewall of said premixer is freely rotatively peripherally and axially displaceably supported by said flange.

12. A mixer as claimed in claim 9, wherein the last-mentioned support comprises a plurality of compressed fluid-controlled cylinders evenly distributed over and extending from said flange, said cylinders having pistons and piston rods with the upper ends of said rods slidably engaging a circular guide of said sidewall.

Description:
The present invention relates to concrete and the like mixing machines, more particularly to mixers of the type comprising a relatively flat and preferably cylindrical main mixing trough or container housing the mixing tools or devices.

A major problem in the design and operation of mixers of the foregoing type is the time required for the carrying out of a concrete or the like mixing operation. This time factor is determined primarily by the construction and effectiveness of the mixing tools within the mixing container, on the one hand, and the time required for the removal or discharge of the mixed aggregates or materials, on the other hand.

A possibility to expedite the mixing operations consists in the separate premixing of the aggregates in a premixer disposed exteriorly of the main mixing machine and in subsequently introducing the sufficiently premixed materials into the main mixer for completion of the mixing operation. Such premixing may be effected simultaneously with the measuring, as to weight or volume, of the aggregates before, during, or after transit to the main mixing site.

An important object of the present invention is the provision of an integrated premixing and main mixing machine, to enable the premixing of the aggregates or raw materials to be effected efficiently and expeditiously prior to their introduction into the main mixing machine.

Another object of the invention is the provision of a structurally combined premixer and main mixing machine of the referred to type which is both simple in design as well as expeditious and reliable in operation, and which will enable a substantially instant transfer of the premixed materials or aggregates from the premixer to the main mixing machine.

The invention, both as to the foregoing and ancillary objects as well as novel objects thereof, will be better understood from the following detailed description, taken in conjunction with the accompanying drawings forming part of this disclosure and in which:

FIG. 1 is a schematic side view, shown partly in section, of a concrete and the like mixer embodying the principles of the invention;

FIG. 2 is a view similar to FIG. 1, showing a modification of the invention; and

FIG. 3 is a plan view of FIG. 2 shown with the feeding devices of the latter omitted.

Like reference numerals denote like parts in the different views of the drawings.

With the foregoing objects in view, the invention involves generally the provision of a mixing machine of the referred to type comprising essentially an open-topped main mixing trough or container immediately above which is disposed a premixer in the form of an open-topped cylindrical container having a sidewall and a rotating bottom wall driven by a suitable power source about its vertical axis. The lower edge of said sidewall, being suitably peripherally supported for free rotation coaxially with said bottom wall, normally frictionally engages said bottom wall, to form therewith a rotating premixing container, suitable feeding means being provided to charge the same with the aggregates or materials to be mixed. Further, according to the invention, there are provided means to temporarily relatively axially displace said side and bottom walls of the premixing container, to provide a peripheral annular passage for the discharge of the premixed materials into the main mixing container by gravity, centrifugal action, etc., in a manner as will become more apparent as the description proceeds.

According to one aspect of the invention, to provide a discharge passage for the premixed materials, the bottom wall of the premixer is slightly lifted by the aid of a hydraulic or the like actuator, for which purpose its drive shaft may be constructed in a known manner of two parts connected for rotation with each other but relatively shiftable in the axial direction.

According to another embodiment of the invention, the cylindrical sidewall of the premixer, being preferably freely rotatively supported by a flange of the preferably also cylindrical main mixing container, is temporarily lowered by the provision of suitable extensible and retractable supporting means, as described in greater detail below.

By a mixing machine of the foregoing general type, the entire mixing operation is expedited considerably, while requiring a minimum of additional constructional parts or mechanism.

In either embodiment of relatively disengaging the side and end walls of the premixer, it is advantageous to provide a bottom wall having the form of a flat cone and to utilize a sidewall provided with an inwardly bent lower skirt forming an annular discharge chute in the disengaged position of the parts. The discharge of the premixed materials is greatly facilitated in this manner, these and other details and advantages of the invention becoming more apparent as the description proceeds in reference to the drawings.

Referring more particularly to FIG. 1, there is shown schematically and by way of example a main mixing trough or container 1 of a concrete or the like mixing machine according to the invention, said trough, in the example shown, having the form of a flat and open-topped cylinder and serving to house the mixing tools or devices (not shown) which may be of conventional construction.

Disposed above the container 1, in the example shown, are a weighing scale and feeder 2 and the upper end 3 of a feed elevator 4 carrying a hopper 5, for the feeding of the components or aggregates to be mixed in the desired proportions. As will be understood, any other known feeding means for the supply of the raw materials to the mixer in the desired proportions may be provided for the carrying into effect of the invention.

Further disposed, in accordance with the improvements of the present invention, above the mixing container 1 and below the feeding devices 3 and 5 is an open-topped premixing container 6 consisting essentially of a circular bottom wall 7, preferably in the form of a flat cone as shown, and a cylindrical sidewall 9 coaxial with the cone 7 and main mixing container 1. The bottom wall 7 is supported, in the example shown, for rotation about its axis by a suitable power source (not shown) on the one hand, as well as for axial displacement in the upward direction, as indicated in dashed lines in the figure. Displacement may be by the aid of a hydraulic or the like actuator 8.

As an example, item 8 may include the power source or driving motor, in which case axial displacement of the bottom 7 may be effected in a known manner by connection of the motor with the bottom wall 7 through a pair of axially slidable shafts locked against rotation relative to one another. Normally, the sidewall 9, being suitably peripherally supported for free rotation about its axis, has its lower end arranged for frictional coupling engagement with the edge portion of the cone 7, to form a closed premixing chamber or container 6, as shown by full lines in FIG. 1. As a consequence, the container 6 will be rotated by the driving source via the bottom wall 7 for the premixing of the aggregates or materials supplied by the feeding devices 2 and 5. Advantageously, the sidewall 9 is peripherally freely rotatively supported, via rollers 10, by a flange or rail 11 extending outwardly from the upper edge of the main mixing container 1, as shown in the example illustrated.

In order to provide adequate friction between the cone 7 and cylinder 9 of the premixing container 6 in the operating position, the lower edge portion of the cylinder is advantageously angularly bent in the inward direction, to provide an inclined annular peripheral skirt 12 being engaged by the edge of the cone 7 in its lowered (full-line) position, in such a manner as to result in an effective friction coupling of the parts.

In operation, the bottom wall 7 being rotated by suitable driving means carries with it the sidewall 9 by friction in the manner described, whereby to result in rotation of the premixer and uniform mixing and distribution of the aggregates over the entire circumference of the bottom 7.

After the aggregates have been sufficiently premixed in this manner, they are transferred to the main mixing container 1 of the machine simply by lifting the cone or bottom wall 7 from the full-line to the dashed-line position shown in the drawing. As a consequence, there is formed thereby an annular peripheral discharge passage between the bottom wall 1 and the skirt 12 of the sidewall 9, resulting in the automatic discharge of the premixed aggregates or materials to the main mixing container 1 approximately to points or areas near the center of the radius of said container where they will be most effectively subjected to the action of the mixing tools. Due to this premixing of the aggregates and their uniform distribution over the circumference of the mixing container, a considerable saving results of the work to be expended by the main mixing devices. This in turn greatly reduces the allover mixing time.

As will be understood, discharge of the mixed aggregates is greatly facilitated both by the conical construction of the bottom wall 7 and the effect of the skirt 12 acting as a discharge chute, as well as by centrifugal action as a result of the rotation of the cone carrying the materials being mixed.

Referring to the embodiment shown by FIGS. 2 and 3, the bottom wall 7 of the premixer, being rotated about its axis by means of suitable driving means (not shown), remains at a fixed height, while the sidewall 9, being supported to rotate freely and driven by friction coupling with the wall 7, is temporarily lowered, as indicated by dashed lines in the drawing, to provide a peripheral annular discharge passage for the premixed aggregates, in substantially the same manner as in the embodiment according to FIG. 1.

There are provided for the latter purpose in FIG. 2 and 3 a number of actuators or extenders 14 interposed between the rail or flange 11 of the main mixing container 1, on the one hand, and a flange or guide extending from the upper edge of the wall 9 of the cylinder 9, on the other hand. In the case of hydraulic actuators 14 distributed evenly over the circumference of the device, as shown in FIG. 3, the actuators may consist of hydraulic cylinders extending upwardly from the flange 11 and containing pistons having piston rods the upper ends of which carry balls or rollers slidably supporting the suitably shaped guide flange disposed at the upper edge of the wall 9.

An advantage of the latter embodiment is due to the fact that the wall 9 of the premixing container 6 may be readily and instantly lowered for the discharge of the contents of the premixing container, while the bottom wall 7 continues to rotate, whereby to expedite the discharge of the materials into the main mixing container through the entire annular passage between the parts, in substantially the same manner as in the case of the FIG. 1 embodiment.

As can be readily seen, the premixer may be charged and/or operated during operation of the main mixing machine, whereby to result in a further substantial reduction of the total mixing time, in a manner readily understood.

The feeding of the raw materials to be mixed to the premixer, such as the concrete raw material and the admixtures or remaining aggregates, is immaterial as far as the function and operation of the present invention is concerned.

In the case of a concrete mixer, the raw materials are advantageously supplied by the weighing scale 2, while the admixtures are supplied by a feeding hopper or the like feeding device. Irrespective of the method of feeding, the components by being applied to the rotating bottom wall 7, are intimately mixed and distributed before being transferred to the main mixing container of the machine.

In the foregoing the invention has been described in reference to an exemplary and illustrative device. It will be evident that variations and modifications, as well as the substitution of equivalent parts and devices for those shown herein for illustration, may be made in accordance with the broader scope and spirit of the invention.