Screeding apparatus
Kind Code:

An apparatus for pivoting a screed assembly during screeding of placed and/or poured, uncured concrete or like loose, spreadable materials to maintain proper screeding contact by the screeding assembly with the concrete or like material by maintaining the predetermined levels of concrete or other like material acting against the screed assembly as it is moved along the concrete. The apparatus requires a support preferably of the self-propelled type, having a boom and a boom mount. The axis of the pivot extends generally perpendicularly to the screeding direction in which the screed assembly is moved. A power source, such as a fluid cylinder rotates the screed about the pivot axis, preferably in response to a leveling sensor mounted on the screed. The lateral incline of the screed perpendicular to the screeding direction may also be separately controlled. A power operated elevation control is preferably responsive to a fixed laser beam reference plane positioned externally of the screed assembly. The screed preferably includes a novel lightweight and is vibrated electrically rather than mechanically vibration assembly is vibrationally isolated from the remainder of the screed for smoothing the concrete.

Johnson, Jack (Galesburg, IL, US)
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What is claimed:

1. An improved screed apparatus for loose or plastic materials for mounting on a separate moveable power support means, said screed apparatus including means for mounting said screed assembly on a boom of said power support means the improvement comprising a. The screed assembly being rigid and elongated and including power means, a striker fur engaging and spreading the material, on a pre-selected plane, rotatable auger means for moving any material above the plane along the direction of the elongation of said screed assembly, sensing and power means for determining deviation from the grade elevation of the screed assembly, and vibration means for engaging, vibrating and smoothing said material; b. The rigid screed assembly is pivotally mounted about a single axis extending parallel to direction of elongation whereby the screed contact with the material may be set and sensed and maintained on predetermined plane.

2. The screed apparatus of claim 1, wherein said power means for rotating said screed assembly maintains the a pre-selected plane through the operative extremities of said striker, said auger and said vibrator at a pre-determined slope/angle and elevation with relation to said material.

3. The screed apparatus of claim 2, wherein said striker and said vibratory units are elements of said screed apparatus made of aluminum.

4. The screeding apparatus of claim 2, wherein said screed includes elevation means for vertically raising and lowering said screed assembly with respect to said materials.

5. The screed apparatus of claim 4, wherein said elevation means includes a pair of elevation tubes secured to said screed assembly at opposite ends of said screeding apparatus, power means for raising and lowering said elevation tubes with respect to said material.

6. The screed apparatus of claim 4, including desired elevation and slope control means responsive to variation from said settings to return and maintain said settings of level and/or slope values.

7. The screeding apparatus of claim 2, wherein said vibration means includes a u-shaped channel member integral with said rigid screed.

8. The screed apparatus of claim 7, wherein said vibration means includes electric vibrators for vibrating said channel member of claim 7, said channel is vibrationally isolated from remainder of said screed.

9. The screed apparatus of claim 6, wherein said control means includes power means to rotate said screed assembly.

10. The screed apparatus of claim 5, wherein said elevation means raising and lowering includes a laser beam responsive control means on said screed assembly responsive to a fixed laser reference plane beam.



The invention is an improved screeding apparatus for attachment to a boom from a power unit. The improvement includes a screed assembly which is light weight and unitary, i.e. rigid framework and operable units, i.e. striker, rotatable auger means for moving the material in direction of auger screw, and vibrating means for engaging, vibrating and smoothing the material, are always on one plane.

The screed assembly is mounted to pivot about the axis of a rotatable auger means whereby controlled contact of the striker and vibration means is or may be controlled by rotation of the screed assembly about the axis of the auger means whereby the contact of the striker and the vibration unit and the auger means with the material is on one plane. Elevation means for raising and lowering the screed assembly with respect to material to be smoothed. This is accomplished by the elevation means which is operable in response to fixed laser beam or beams, so that the screed may have the plane of the screed assembly parallel to the auger means modified to control the elevation and grade in conjunction with the controlled rotation of the screed assembly.

This results in the lateral tilt of the screeding assembly as well as for the plane of the striker, auger and vibration means.

The elevation control tubes or means are secured directly to the ends of the screed assembly so that the plane of the screed assembly is at right angles to the direction of movement of the screed assembly.

Sensing means including setting of desired values of grade and/or elevation of the screed with reference to the material are an integral part of the screed assembly. To ascertain variations from the settings of the elevation and or grade the sensor will signal the elevation units and the rotational unit to planes not units of change to maintain the desired elevation and grade.

The screeding apparatus of this invention provides improvements and advantages over prior screeding assemblies.

The unitary structure of this novel screeding structure provides for improved control of the screeding unit with respect to maintaining desired grade and elevation with only one control and only one axis as reference a point.

The rigidity of the structure allows for weight reduction by using lighter materials to form the rigid structure and to utilize planes of structures to simplify the unit.

The novel vibrational unit reduces weight, power requirements and avoids the necessity for frequent sag adjustments of the vibrational unit.

Also reduces the force required for vibration because of the screed vibrational material thickness and shape. A disadvantage to this screed is that it requires a separate source of motive power to move the screed and to provide power either hydraulic and/or electrical for the auger and other functions.

This screeding assembly allows rotation of the screeding assesmbly as a unit about a single axis and provides an improved vibratory system that requires less power and also does not require frequent adjustments of the vibratory elements and/or adjustments of the screed surface for smoothing the material.

These and other objects advantages and features of the invention will become more apparent from a study of the following description.


FIG. 1 is a rear side view of the screeding apparatus of the present invention as mounted on a boom from a motive power apparatus.

FIG. 2 is an end view of the screeding apparatus of the present invention.

FIG. 3 is a rear view of the screeding apparatus of the invention showing the operating elements.

FIG. 4 is a top view of the invention.

FIG. 5 is schematic view of the electronics of the invention.

FIG. 6 is a schematic view of the fluid controls to various elements of the invention.


Laser Beacon reference Plane Control system for controlling elevation of screed assembly including elevation tubes 501 and 502 is substantially similar to that used in U.S. Pat. Nos. 4,655,653 and 4,930,935. This includes prior art and laser receiving mounting masts 501, 502. A laser beacon 510 receive is removably secured to each of said masts 501 and 502.

The necessary data and controls are set forth in Col. 19 and Col. 20 lines 59, Col. 19 to line 50, Col. 2. of U.S. Pat. No. 4,930,935 will form part of the control as sensor 600 measures the deviation of the screed assembly from the desired or present positions to determine the elevation and position of plane between extremities or working surface of striker 202 and vibratory unit 300.

Sensor 600 may be a blade level sensor such as a sensor part number 421870 and control box 421871 of Trimble which will be placed on end plate 104 as shown in FIG. 1. This level sensor may be preset for limits of the level or plane as described above and/or to be at a predetermined elevation of striker and vibratory units.

The proper plane level for grade purposes is maintained by signals from sensor unit 600 to a corrective cylinder 601 which is affixed to arm 602 in a vertical direction thus, rotating the entire screed, striker and vibratory unit about the pivot axis of the auger. The plane between the striker, and vibratory unit is rotated and changed about a single axis.

Vibratory element 300 comprises an aluminum channel 301, extending the length of the assembly 100. This channel 301 is supported from main beams 101 and 102 by a plurality of vertical members 103 which are vibratoral isolated from said channel 301.

Thus, a small vibratory force furnished by electrical vibration units 305 can vibrate channel 301 to smooth the material.

The rigidity of the support elements 103 combined with the relatively thin channel including the surface contact 306 of the channel 301 helps prevents sag between support elements. This eliminates any adjustments to the vibratory element.

Screed assembly 100 is an improved and novel screed assembly with a unitary assembly including main beams 101, 102 and cross support members 103 and supportive end plates 104. Supporting rotational auger 201, a plow or striker 202 is positioned in front of auger 201, and novel vibratory element 300 is positioned behind rotational auger 201. Auger 201 forms the axis for rotation of the assembly.

Auger 201 assembly is a continuous auger supported from said main beams 101 and 102 and end plates 104 as shown in FIG. 2.

The unitary construction of the screed assembly results in the rotation of the entire assembly about the single axis. The striker and vibratory units are made of aluminum and a uniform movement of the plane determined by the extremities of striker 202 and vibrational element or unit 300.